What is "career mode" and how does this mode differ from the other modes (which are?)? Analyzing the purpose of the different modes might provide you with an answer.
Career mode is a direct simulation of the ATP tennis tour, except you can only play as a player you created, you can't choose a current pro!
King of the court is stupid because it just makes you choose 4 players and they play off against each other, it's not like a real season!
Exhibition mode is obvious, just pick 2 players to play each other!
Online mode (2k Open) is a great idea, I'll play that (though can't play as a current pro - but maybe I'll name myself Rafael Nadal and make his appearance)!1